Kourtney Kardashianand celebrity makeup artist Joyce Bonelli took Kim Kardashian out for a pre-birthday celebration Thursday night in NYC, and the girls were all sporting super chic ’70s inspired styles.

Kim stepped out of her hotel in a pair of eggplant colored high-waisted slacks and a pale pink top that she accessorized with a multi-colored headband. Meanwhile, Kourtney went for a purple printed floor-length dress that she accented with huge earrings.

Which sister’s ’70s style do you prefer? Let us know in the comments!

After their night of ’70s outfits, Kourtney was ready to party in another decade! The reality star tweeted to her sister on Friday:

“Happy birthday to my favorite sister of the day @KimKardashian! Let’s party like it’s 1980!”